POA vs. DPOS Advantages and Disadvantages


Hi Everyone,

I was wondering what the main advantages and disadvantages are between DPOS and POA?
Thanks in advance.



We talk a lot about the advantages of POA based networks such as vertical and horizontal scalability, irresistibility to use, interoperability with other chains for both native and erc tokens. Let me outline some disadvantages of the POA model.

In networks like POA Core/ xDai Chain with the exclusive group controlling the validator set, there is no possible economic mechanism to change the membership in the set. This creates more incentive for the exclusive group of validators to keep the status quo, e.g.

  • take fewer risks with network upgrades. On 2019-03-14T23:00:00Z POA Core: Byzantium and Eth Mainnet: Constantinople patch set. xDai validators are more incentivized and have Constantinople enabled
  • take fewer risks with spending funds of EmissionFunds. There are no EmissionFunds on xDai.
  • don’t increase the number of validators for the recommended parameters based on academic research. There are 25 candidates in line based on Table #3 — POA Network Validator Candidates. There are 4 pending applications for xDai.

There is no clear process of removing from the validator set based on misbehaving. After more than a year of the operation, the validators of POA Core didn’t publish an operational plan with the Service Level Agreement between the ValidatorSet DAO and the participants of the network. The same with xDai Chain where outage decreases the overall speed of the block producing. Misbehaving should be penalized and there is no clear agreement between the DAO and users of the network.

On the other hand, the DPOS model creates an open market for participation in validator set and sharing the reward with the token holders. The security model requires slashing/freezing of misbehavior and usually included in the protocol. The model tends to be more open and vertically scalable. We plan to release the new model and paper in the POSDAO forum subcategory.
The model combines the best of two worlds (POA and DPOS). Stay tuned and watch for the updates.